With the extra specialty plan, the employee would not be permitted to establish or contribute to an HSA. Participation in an HSA is limited to individuals who are covered under a high deductible health plan (HDHP) and who are not also covered under any other health plan (with the exception of limited types of “permitted insurance”), eligible for Medicare (i.e., age 65 or older), or eligible to be claimed as a dependent on another person's tax return.
Therefore, to be eligible to contribute to an HSA, the employee would have to have an HDHP and no other insurance, except specified “permitted insurance.” Permitted insurance includes insurance for a specified disease or illness, and insurance paying a fixed amount per day (or other period) of hospitalization. Insurance for specified services, such as acupuncture or chiropractic care, does not fit the definition of permitted insurance.
If, for example, the employee were instead covered by insurance that paid or reimbursed him for expenses for vision, dental and preventive care, or for treatment for a specific disease such as cancer, or for daily fixed payments for hospitalization (as long as the principal coverage is provided by the HDHP and the permitted coverage is provided through insurance contracts, not through self-insurance) or which paid and reimbursed health plan premiums, he would be eligible to contribute to an HSA.
Note that workers' compensation or other statutorily required benefits are exempted from the “insurance contract” requirement for “permitted insurance.”
Source: Code Sec. 223.